There have been several recent efforts to incorporate reactive arylcyclobutene groups in condensation polymers. For example, in U.S. Pat. No. 4,708,994 it is taught to incorporate reactive arylcyclobutene groups by means of alkylating or acylating aromatic groups of such resins with a molecule containing a reactive arylcyclobutene moiety to provide pendant arylcyclobutene moieties randomly along the polymer backbone. Unfortunately, however, these processes are not efficient or selective in incorporating reactive arylcyclobutene moieties. Moreover, the materials having random and uncontrolled crosslinking throughout the polymer backbone are found to possess generally unsatisfactory combinations of other physical properties such as toughness.
In U.S. Pat. Nos. 4,795,827 and 4,825,001 cyclobutarene ketoaniline monomers are used for attaching cyclobutarene groups to polymers or other molecules having amino-reactive functionalities, including ester- or ether-type polymers The cyclobutarene groups are then employed to form crosslinked or polymerized compositions. However, due to the requirement for amine reactivity and due to the nitrogen atoms used in creating the linking groups, the use of these monomers in condensation polymers is limited. For example, desirable carbonate-type condensation polymers having arylcyclobutene moieties could not be prepared by the technique of U.S. Pat. Nos. 4,795,827 and 4,825,001 due to the unacceptable instability of the carbamate groups that would necessarily result from the use of such monomers. In addition, the use of such a technique to prepare the arylcyclobutene-functionalized condensation polymers requires the multiple steps of preparing or otherwise obtaining the initial polymer to be functionalized followed by the separate step of attaching the cyclobutarene ketoaniline monomers.
In U.S. Pat. No. 4,864,010 benzoxazole linked bis-arylcyclobutenes are prepared from condensation reacting a cyclobutarene-carboxylic acid, a diaminodihydroxyarene, and optionally an aromatic diacid or diacid chloride.
It would therefore be desirable to have an improved, efficient process for preparing a broad range of carbonate- and/or ester-type condensation polymers having terminal arylcyclobutene moieties and possessing good combinations of product properties, including toughness, solvent resistance, heat resistance, and thermal stability.